Apparatus and process for insulating and twisting strands



H. BURR Sept. 11, 1962 APPARATUS AND PROCESS FOR INSULATING AND TWISTING STRANDS Filed Jan. 24, 1961 INVENTOR.

HARVEY BURR 3 053,037 APPARATUS AND PI QOCESS FOR INSULATING AND TWISTING STRANDS Harvey Burr, Hastings on Hudson, N.Y., asslgnor to Anaconda Wire and Cable Company Filed Jan. 24, 1961, Ser. No. 84,692 8 Claims. (Cl. 57-12) My invention relates to the application of wrapped tapes or servings to elongated strands and particularly to apparatus and process for the combined wrapping of the individual strands and twisting of pairs for telephone cables.

In the manufacture of strip-insulated telephone cables narrow tapes of insulating material are wrapped around copper wires to produce insulated conductors. Tape winding machines are customarily used for this operation and the insulated conductors are taken up on reels in the tape winding machines for storage and further processing. Since telephone cables are most commonly made up of twisted pairs each consisting of two insulated conductors twisted together with a predetermined length of lay, the next major operation in the manufacture of a telephone cable after the conductor wires have been wrapped with insulating tape is usually the twisting of two of the insulated wires to form a twisted pair. For this purpose the reels of insulated conductor are removed to another machine known variously as a twister, a twinner, or a strander. In the twister two individually insulated wires are spiralled together to form a twisted pair, and the product supplied by a twister will consist of a reel or of some other form of package containing va single continuous length of the twisted pair so formed.

In a later step in the manufacture of a telephone cable, this, along with other reels of twisted pair will be removed to a cabling machine where the pairs will be twisted with other pairs to form a cable core. From the foregoing it will be seen that the manufacture of a twisted pair by known methods requires two different operations. These operations are the wrapping of strip insulation onto wires and the twisting of the insulated wires into pairs.

Manufacturing operations in which elongated strands are first wrapped or served with a covering material and then twisted together are not, however, limited to the telephone cable art or to the wire and cable industry, and my invention is not to be construed as being so limited.

It is an object of the apparatus of my invention to combine the two operations of wrapping a covering material onto an elongated strand and twisting two or more strands together, into a single operation.

It is a further object of the apparatus of my invention to apply a wrapped covering to elongated strand in such a manner that the covering will not burst during subsequent twisting of the strands.

I achieve these objectives with apparatus that combines the operation of wrapping insulation onto individual Wires and twisting said insulated wires together. My apparatus comprises means for advancing a plurality of strands along spaced paths at a predetermined speed. It also comprises a forming die for bringing the strands together at the end of their spaced paths and twisting means, downstream of the forming die, for twisting the States Patent drawing a take-up reel 22 rotates on ree strands together. In addition to the foregoing, my apparatus comprises supply stations each supplying a strip of covering material for one of the strands. The supply stations are fixed at points out of the path of'advance of the strands and the apparatus comprises a plurality of wrapping dies each directing one of the strips to one of the strands at a point upstream of the forming die. The strips are wrapped around the strands in consequence of the twisting of the strands around their own axes by the twisting means. Advantageously the wrapping dies may be heated such as by electrical resistance units to ease the passage of the strip through the die, and the forward motion of the strands controlled by gear means between the twisting means and the advancing means.

A feature of one embodiment of my invention comprises an endless belt to advance the strips as they wrap around the strand. The belt is in frictional contact with the strips and may be faced by an opposing belt or by a.

apparatus comprises means for changing the ratio of the belt speed to the strand speed.

My invention emcompasses the process for continuously covering and twisting together a plurality of strands by paying them into a common forming die from stationary supply stations and twisting them by applying a twist downstream of the forming die. In my process, strips of covering material are payed off from supply stations fixed relative to the paths of the strands, each strip extending to one of the strands at a point upstream of the forming die where the strands are still separated from each other. The strips are advantageously heated at the points of application to the strands and wrap around the strands in consequence of the twisting of the strands on their own axes when they are twisted together.

Other objects of my invention will be made obvious from the drawing and detailed description as follows.

In the drawing:

FIG. 1 is a schematic plan view of an embodiment of the apparatus of my invention.

FIgIG. 2 is a schematic side view of the apparatus of FIG. 3 is a plan view of one embodiment of a feature of my invention.

FIG. 4 is an elevation of another embodiment of the feature of FIG. 3.

A combined taping and twisting apparatus indicated generally at 9 in FIGS. 1 and 2 is mounted on a frame or platform 10. A twisting unit 11 has'a frame 12 supported on journals 13, 14 and driven through a belt 15 by means of the motor 16. A plurality of strands 17, 18 pass over the entrance sheave 19, which is fixed to the frame 12 of the twisting unit 11 and rotates with the frame 12 to impart a twist to the strands 17, 18 and thus form a twisted pair 21. The plurality of strands 17, 18 are not necessarily limited to two, and in those cases where more than two strands are twisted the cable core formed will be larger than the twisted pair 21.

In the particular type of twisting unit 11 shown in the a stationary axis while the frame 12, entrance sheave 19, and three additional guide sheaves 23, 24, 25 rotate around it. A twisti-ng unit of the type shown imparts two complete twists to the strands for each revolution of the frame 12, and is preferred when this invention is used in the manufacture of paper-insulated telephone cable pairs. Other forms of twisting mechanisms, particularly forms in which the axis of the reel 22 is perpendicular to the axis of the flame 12, as in the illustrated case, or in which the axis of reel 22 is parallel to the axis of the frame 12 might be employed without lessening the usefulnes or novelty contributed by this invention. Some of these alternative forms impart only one twist to the strands rather than the double twist imparted by the preferred form of the twisting unit 11. In the twisting unit 11 the twisted pair 21 passes over the sheaves 23, 24 and 25 through a traverse guide 26 onto the reel 22. Sheave 25 since it is rotating relative to reel 22 imparts an additional twist to the twisted pair 21.

The strands 17, 18 are supplied from stationary and non-rotating reels 31, 32 through guide sleeves 33, 34 to a grooved double-pulley pay-E capstan 35. The reels 31, 32 are stationary in the sense that they have no planetary motion about the axis of advance of the strands 17, 18 and they are non-rotating in the embodiment shown in the drawing in the sense that the strands 17, 18 are flipped over the flanges of the reel rather than turning the reels 31, 32 on their axes. However, apparatus wherein the strands are payed from rotating reels on axes stationary with reference to the path of advancement of the strands, will also be included within the scope of my invention. Other strand pay-off means are known, and the scope of this invention is not limited to the pay-off reel arrangement shown in the drawing.

The speed of the capstan 35 determines the speed of the forward motion of the strands 17, 18, consequently, when the rotational speed of the frame 12 remains constant the length of lay of the twist in the twisted pair 21 will depend on the speed of the capstan 35. The capstan 35 is driven by the motor 16 through change gears 36 and 37, shaft 38, bevel gears 41, 42 and a shaft 43. After leaving the capstan 35, strands 17, 18 pass around vertical guide rolls 44, 45 and through a lay plate 46. The lay plate 46 keeps the strands 17, 18 separated and they pass from the lay plate 46 into a forming die 47.

When the frame 12 rotates it imparts torsion to each of the strands 17, =18. This torsion carries back through the lay plate 46 twisting each of the strands 17, 18 around its own axis. Pads 48, 48a of strip insulation are shown schematically in the drawing to be rotatable about pins 49, 50 but the pads 48, 48a are stationary in the sense that they do not have any planetary motion around the path of advancement of the strands 17, 18. Paper is commonly used for telephone cable pairs but tapes of a plastic material such as polyethylene may be applied, or a plurality of ends of textile material such as combed cotton yarn. A tape 51 is applied to the strand 17 from the pad 48 through a die 53 and another tape 52 is applied to the strand 18 from the pad 48a through a die 54. As the strands 17 and 18 pass through the lay plate 46 they carry the tapes 51, 52, forward with them. The dies 53, 54 may be heated through leads 55 from an electrical power source 56.

The tape 51 is wrapped around the strand 17 due to the back twist in the strand resulting from the rotation of frame 12. Similarl; the tape 52 is wrapped around the strand 18. No tape winding equipment is required to wrap the insulating strip around the individual strands and the insulated strands advance directly into the twister without intermediate steps of winding onto reels and unwinding therefrom which intermediate Workings would have a hardening effect on the wire and could not help but disarrange to some degree the evenness of the tape wrappings.

It has been known to separate the forming die 47 a considerable distance from the twister 11 and then to take advantage of the rotation of the twisted pair or core to wrap tape over the combined strands at a point between the die '47 and the entrance to the twister 11. A novel feature of my invention resides in the application of tape to each of the individual uncombined strands by virtue of the rotation imparted to them by the operation of stranding or twisting a number of strands together.

In one embodiment of my invention, particularly suited for use with paper tape insulation, an upper endless belt 61 is placed in contact with the upper surface of the strands 17, 18 and a lower endless belt 62 is in contact with the under surfaces of the strands 17, 18. The belts 61, 62 are preferably made from rubberized fabric and are driven, both at the same linear speed, by means of a variable speed gear 63 and bevel gears 64, 65 from the drive shaft 38. By means of the variable speed gear 63 the speed of the belts 61, 6 2 can be varied at will. In addition the endless belts 61, 62 can be rotated about a vertical axis to vary the angle bet-ween the axis of motion of the belts and the axis of motion of the strands 17, 18.

FIGS. 3 and 4 show one embodiment of an assembly for the upper endless belt 61 and show details of the mounting of the belts that have been omitted from FIGS. 1 and 2 for the sake of clarity. The assembly of the lower endless belt 62 is analogous. The belt 61 is mounted over rolls 66, 67 rotatably fixed in support 68. Roll 66 is driven through an extension of its shaft 69 terminating in a clevis 70 which forms a part of the telescopic universal joint 71.

The support 68 has a vertical stub shaft 72 rotatably mounted in a bearing 73. The bearing is adjustably mounted in angular relation to the axes of the strands 17, 18 by means of the arm 74 which is, in turn, rigidly fastened as by welding to a post 75 vertically mounted on the platform 10, a collar 76 locked to the stub shaft 72 by a set screw 77 prevents the stub shaft 72 from dropping out of the bearing 73. Another set screw 78 locks the stub shaft 72 in a fixed angular position in the bearing 73.

Since the strands 17, 18 are rotating at the same time as they are moving forward, any point on the upper surface of one of the strands 17, 18 will have a resultant motion at an angle to the axis of forward motion of the strands. A pointer 79, parallel to the axis of motion of the upper belt 61 in conjunction with an arcuate scale 80 shown diagrammatically in FIG. 3 can be used to adjust the angle of motion of the belt 61 to coincide with the angle of motion of points on the upper surface of the strands 17, 18. The scale 80 is mounted to the platform 10 between two vertical posts 81, 82. In like manner the angle of motion of the endless belt 62 can be adjusted to the motion of points on the lower surface of the strands 17, 18. The belts '61, 62 may be wide enough to cover a plurality of the strands 17, 18 feeding into the twister 11 or individual belts may be applied to each strand.

When the belts 61, 62 are used they are applied to the taped strands 17, 18 after they leave the dies 53, 54. The speed and angle of the belts 61, 62 are adjusted to cause the tapes 51, 52 to advance faster than the strands 17, 18 so that the tapes are applied loosely on the strand. (This can be done readily when the tape has a degree of stiifness such as is characteristic of paper. For softer tapes such as polyethylene, however, I prefer to omit the belts 61, 62.) Such loosely applied tape covering will not rupture in passing over sheaves 19, 23, 24, 25, and in receiving the additional twist imparted between the sheave 25 and the reel 22 as heretofore noted.

In an alternative embodiment of the belt feature of my invention, shown in FIG. 4, the lower belt has been supplanted by a polished plate 83 having a ledge 84. The ledge 84 may also have the form of a shallow groove in the surface of the plate 83 and prevents the wire 18 from being pushed to the right by the motion of the belt 61.

It is an advantage of my invention that the tape supply pads 48, 48a are fixedly mounted and do not rotate around the wires 17, 18. It has been known that the taping and twisting operations might be combined by rotating the tape supply pads around the wires entering the twister but such apparatus would be complicated and expensive. My discovery that tape can be supplied from pads on stationary axes into the individual wires paying into a twister has had the beneficial effect of eliminating the need for additional rotating equipment.

I claim:

1. Apparatus for individually covering and twisting together a plurality of strands comprising means for advancing said strands along spaced paths at a predetermined speed, a forming die located at the end of said paths for bringing together said strands, twisting means downstream of said forming die for twisting together said strands, a plurality of supply stations each supplying a strip of covering material for one of said strands, said supply stations being each at a point out of the paths of advance of said strands, a plurality of wrapping dies in the spaced paths of said strands, each of said wrapping dies directing one of said strips to one of said strands at a location on the path of said strand upstream of said forming die, said strips being wrapped around said strands in consequence of the twisting of said strands on their axes by said twisting means.

2. Apparatus for individually covering and twisting together a plurality of strands comprising means for advancing said strands along spaced paths at a predetermined speed, a forming die located at the e11 d of said paths for bringing together said strands, tw st ng means down-stream of said forming die for twisting together said strands, a plurality of supply stations each supplying a strip of covering material for one of said strands, said supply stations being each fixed at a po nt out of the paths of advance of said strands, a plurality of wrapping dies in the spaced paths of said strands, each of said wrapping dies directing one of said strips to one of said strands at a location on the path of said strand upstream of said forming die, means for heating said wrapping dies, said strips being wrapped around said strand in consequence of the twisting of said strands on their axes by said twisting means.

3. Apparatus for individually covering and twisting together a plurality of strands comprising means for advancing said strands along spaced paths at a predetermined speed, a forming die located at the er1 d of said paths for bringing together said strands, twisting means downstream of said forming die for twisting together said strands, gear means connecting said advancing means to said twisting means whereby said strands will be caused to advance at a preselected distance for each revolution of said twisting means, a plurality of supply stations each supplying a strip of covering material for one of said strands, said supply stations being each fixed at a point out of the paths f advance of said strands, a plurality of wrapping dies in the spaced 55 paths of said strands, each of said wrapping dies directing one of said strips to one of said strands at a location in the path of said strand upstream of said forming die, said strips being wrapped around said strands in consequence of the twisting of said strands on their 0 aXes by said twisting means.

4. Apparatus for individually covering and twistini together a plurality of strands comprising means for advancing said strands along spaced paths at a predetermined speed, a forming die located at the end of 65 said paths for bringing together said strands, twisting means downstream of said forming die for twisting together said strands, a plurality of supply stations each supplying a strip of covering material for one of said strands, said supply stations being each fixed at a point out of the paths of advance of said strands, a plurality of wrapping dies in the spaced paths of said strands, each of said wrapping dies directing one of said strips strand upstream of said forming die, at'least one end less belt in frictional contact with said strips downstream of the location where said strips are wrapped around said strand, said belt advancing said strips and said strips being wrapped around said strands in consequence of the twisting of said strands on their axes by said twisting means.

5. Apparatus for individually covering and twisting together a plurality of strands comprising means for advancing said strands along spaced paths at a predetermined speed, a forming die located at the end of said paths for bringing together said strands, twisting means downstream of said forming die for twisting together said strands, a plurality of supply stations each supplying a strip of covering material for one of said strands, said supply stations being each fixed at a point out of the paths of advance of said strands, a plurality of wrapping dies in the spaced paths of said strands, each of said wrapping dies directing one of said strips to one of said strands at a location on the path of said strand upstream of said forming die, two endless belts in frictional contact with said strips downstream of the location where said strips are wrapped around said strand, means for driving said belts in proportion to the speed of advancement of said strands, variable speed control means for changing said proportion, said belts being adjustably mounted on an axis normal to the axis of said strands on opposite sides thereof and forming angles with said strand of equal degree but of opposite sign, said belts advancing said strips and said strips being wrapped around said strands in consequence of the twisting of said strands on their axes by said twisting means.

6. Apparatus for individually covering and twisting together a plurality of strands comprising means for advancing said strands along spaced paths at a predetermined speed, a forming die located at the end of said paths for bringing together said strands, twisting means downstream of said forming die for twisting together said strands, a plurality of supply stations each supplying a strip of covering material for one of said strands, said supply stations being each fixed at a point out of the paths of advance of said strands, a plurality of wrapping dies in the spaced paths of said strands, each of said wrapping dies directing one of said strips to one of said strands at a location on the path of said strand upstream of said forming die, an endless belt in frictional contact with said strips downstream of the location where said strips are wrapped around said strands, means for driving said belt at a speed proportional to the speed of advancement of said strand, a smooth plate disposed on the opposite side of said strands from said belt, said belt constraining said strands against said plate, said belt advancing said strips and said strips being wrapped around said strands in consequence of the twisting of said strands on their axes by said twisting means.

7. The process of covering and twisting together a plurality of strands in one continuous operation comprising paying ofi a plurality of said strands each from a stationary supply station into a common forming die, twisting together said strands at said die by applying the twist downstream of said die, paying off a plurality of strips of covering material from supply stations fixed relative to the paths of said strands, each of said strips extending from one of said supply stations to one or said strands at a point upstream of said forming die, said strands being separated from each other at said point, said strips forming spiral wraps around the respective individual strands by reason of the twisting around their own axes of said strands imparted by said twisting together of the strands.

8. The process of covering and twisting together a plurality of strands in one continuous operation comprising paying off a plurality of said strands each from a stato one of said strands at a location on the path of said tionary supply station into a common forming die, twist- 8 ing together said strands at said die by applying a twist of said strands on their own axes by said twisting together downstream of said die, paying ofl a plurality of strips of the strands. of insulating material from supply stations fixed at a point out of the paths of said strands, each of said References Cited in the file of this Patent strips extending from one of said supply stations to one 5 UNITED STATES PATENTS of said strands at a point upstream of said forming die, 2 347 631 Hotchkiss APR 25, 1944 said strands being separated from each other at said point, 2:947:652 Aug. 2 1960 heating said strips at the points of application to said strands, said strips forming spiral wraps around the re FOREIGN PATENTS spective individual strands in consequence of the twisting 10 1,072,160 Germany Dec. 24, 1959 

